Choose the correct order of the given alternative : F _ U6 _ 9I _ T7 _ 20 _ 4D23

Explanation:-

From the alternatives, it is clear that the series can be divided in to 4 groups of four terms each - each group comprising of two letters and two numbers, occurring alternately..
F _ U6/ _ 9I _ / T7 _ 20 / _ 4D23
4D indicates that in a group, the number at the second place denotes the position of the letter at the thired place, in the English alphabet.
T7 _ 20 indicates that in a group, the number at the fourth place denotes the position of the letter at the first place, in the English alphabet.
Thus, putting A = 1, B = 2......Y = 25, Z = 26. we have ,
1st missing term = U = 21;
3rd missing term = 7th letter = G
5th missing term = 23 letter = W.